C#•2mo ago

Calculating Student Grade Book Average (GBA) in Percent - Encountering Zero Value Issue

I'm working on a student class with properties mark and totalMark. My goal is to define the totalMark property to compute the GBA as a percentage. However, every time I implement the calculation, the totalMark value consistently returns 0.

c#
  public class Student
{

    private int totalmarks;

    public string? Name { get; set; }

    public int Marks { get; set; }

    public int TotalMarks
    {
        get
        {
            return (this.Marks / 250) * 100;
        }
    }

}

Student student = new Student();

student.Marks = 120;

int gba =  student.TotalMarks;

Console.WriteLine(gba);

c#
  public class Student
{

    private int totalmarks;

    public string? Name { get; set; }

    public int Marks { get; set; }

    public int TotalMarks
    {
        get
        {
            return (this.Marks / 250) * 100;
        }
    }

}

Student student = new Student();

student.Marks = 120;

int gba =  student.TotalMarks;

Console.WriteLine(gba);

45 Replies

SG97•2mo ago

Don't use an int You could try decimal

steven preadly•2mo ago

for the total marks or for the marks

SG97•2mo ago

Total

Angius•2mo ago

And make sure to make at least one part of the equation a decimal

SG97•2mo ago

Ah yes

Angius•2mo ago

public decimal TotalMarks => Marks / 250m * 100;

public decimal TotalMarks => Marks / 250m * 100;

for example

Mayor McCheese•2mo ago

do you understand why you're getting zero?

steven preadly•2mo ago

i may have done somthing wrong in the equation itself let me check

Angius•2mo ago

The issue is integer division

Mayor McCheese•2mo ago

it's not that, essentialy integers can't carry a fractional number

SG97•2mo ago

It's not the equation per se

MODiX•2mo ago

Angius

REPL Result: Success

7 / 250

7 / 250

Result: int

Compile: 145.894ms | Execution: 16.908ms | React with ❌ to remove this embed.

Mayor McCheese•2mo ago

so the nearest integer is in fact 0

Angius•2mo ago

Meanwhile

MODiX•2mo ago

Angius

REPL Result: Success

7 / 250m

7 / 250m

Result: decimal

0.028

0.028

Compile: 269.572ms | Execution: 18.151ms | React with ❌ to remove this embed.

Mayor McCheese•2mo ago

but also...

MODiX•2mo ago

Mayor McCheese

REPL Result: Success

250/7

250/7

Result: int

Compile: 183.660ms | Execution: 15.366ms | React with ❌ to remove this embed.

steven preadly•2mo ago

what dose the m means

Mayor McCheese•2mo ago

it means treat as a decimal bare numbers in c# have some odd behaviors so... 2.0 is a double, 2.0d is also a double

steven preadly•2mo ago

where can i read about this modifiers

Mayor McCheese•2mo ago

decimal d = 2.0 iirc is a syntax error.

MODiX•2mo ago

Mayor McCheese

REPL Result: Failure

decimal d = 2.0;

decimal d = 2.0;

Exception: CompilationErrorException

- Literal of type double cannot be implicitly converted to type 'decimal'; use an 'M' suffix to create a literal of this type

- Literal of type double cannot be implicitly converted to type 'decimal'; use an 'M' suffix to create a literal of this type

Compile: 226.024ms | Execution: 0.000ms | React with ❌ to remove this embed.

Mayor McCheese•2mo ago

https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/builtin-types/built-in-types

Built-in types - C# reference

Learn C# built-in value and reference types

steven preadly•2mo ago

i re-created my code as below

c#

public class Student
{
    private int _marks;

    private float totalmarks;

    public string? Name { get; set; }

    public int Marks 
    {
        set 
        {
            _marks = value;
        }
        get
        {
            return _marks;
        }
    }

    public float TotalMarks
    {
        get
        {
            return ( _marks / 250f) * 100;
        }
    }

}

c#

public class Student
{
    private int _marks;

    private float totalmarks;

    public string? Name { get; set; }

    public int Marks 
    {
        set 
        {
            _marks = value;
        }
        get
        {
            return _marks;
        }
    }

    public float TotalMarks
    {
        get
        {
            return ( _marks / 250f) * 100;
        }
    }

}

Angius•2mo ago

    private int _marks;
    // ...
    public int Marks 
    {
        set 
        {
            _marks = value;
        }
        get
        {
            return _marks;
        }
    }

    private int _marks;
    // ...
    public int Marks 
    {
        set 
        {
            _marks = value;
        }
        get
        {
            return _marks;
        }
    }

can just be

public int Marks { get; set; }

public int Marks { get; set; }

btw

Mayor McCheese•2mo ago

in most cases autoprops are fine, some older frameworks it doesn't work as well.

steven preadly•2mo ago

and this means that i hcve to use this suffiex every time i am using float decimal or double

Angius•2mo ago

https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/language-specification/lexical-structure#6453-integer-literals here's the list of literals Not always, no

Mayor McCheese•2mo ago

it's best to use the suffix for a bare number imho. but it does depend on the application.

steven preadly•2mo ago

do you mean by bare numbers is numbers that are not assigend to a varible and as i think i dont have to create a private prop in here to , as there is no modification or validation that needs to be done in here

Angius•2mo ago

$getsetdevolve

MODiX•2mo ago

class Foo
{
    private int _bar;

    public int GetBar()
    {
        return _bar;
    }

    public void SetBar(int bar)
    {
        _bar = bar;
    }
}

class Foo
{
    private int _bar;

    public int GetBar()
    {
        return _bar;
    }

    public void SetBar(int bar)
    {
        _bar = bar;
    }
}

can be shortened to

class Foo
{
    private int _bar;

    public int GetBar() => _bar;

    public void SetBar(int bar) => _bar = bar;
}

class Foo
{
    private int _bar;

    public int GetBar() => _bar;

    public void SetBar(int bar) => _bar = bar;
}

can be shortened to

class Foo
{
    private int _bar;
    public int Bar {
        get { return _bar; }
        set { _bar = value; }
    }
}

class Foo
{
    private int _bar;
    public int Bar {
        get { return _bar; }
        set { _bar = value; }
    }
}

can be shortened to

class Foo
{
    private int _bar;
    public int Bar {
        get => _bar;
        set => _bar = value;
    }
}

class Foo
{
    private int _bar;
    public int Bar {
        get => _bar;
        set => _bar = value;
    }
}

can be shortened to

class Foo
{
    public int Bar { get; set; }
}

class Foo
{
    public int Bar { get; set; }
}

steven preadly•2mo ago

@Right Dr. Mayor McCheese Esq. in that code the set the prop to float while it returns ineger 48 thats looks weried to me

c#
  
    public float TotalMarks
    {
        //the get returns integer 
        get
        {
            return (Marks / 250f) * 100f;
        }
    }   

}

c#
  
    public float TotalMarks
    {
        //the get returns integer 
        get
        {
            return (Marks / 250f) * 100f;
        }
    }   

}

Angius•2mo ago

This will return a float

steven preadly•2mo ago

correct me if i am wrong i am using the f in here to make sure that if the value passed if it is not divisivble by the 250 as above it gets the remender

Angius•2mo ago

You're using f here to trigger float division instead of integer division Because Marks and 250 are both integers One of them has to become a decimal type in order to get a decimal out There's nothing about divisibility or remainder You're not using the modulo operator anywhere

steven preadly•2mo ago

execuse my stupidity do you mean that that part will be converted to decimal

(Marks / 250f)

(Marks / 250f)

Angius•2mo ago

To a float Because of the f suffix

steven preadly•2mo ago

and in that part if i made the accessor return int other than float and i removed the f suffix its normal to get a 0 because of lost data pression

Angius•2mo ago

Yes Since integers cannot represent decimal values

steven preadly•2mo ago

got the point i this case i have to use the suffiex with any calculation that i am not sure if is result will be float ,double or decimal

Angius•2mo ago

You decide what the result will be Integer divided by a double will be a double Divided by a float will be a float Etc Could even just cast the original integer, or both, to the same effect. All of those would work to produce a decimal, for example:

Marks / 250m
(decimal)Marks / 250m
Marks * 1m / 250
Marks / (decimal)250

Marks / 250m
(decimal)Marks / 250m
Marks * 1m / 250
Marks / (decimal)250

steven preadly•2mo ago

ok thank you very mush

Mayor McCheese•2mo ago

sorry I was cooking and not paying attention.

steven preadly•2mo ago

no problem

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Calculating Student Grade Book Average (GBA) in Percent - Encountering Zero Value Issue